Find every subdomain
of a domain.

Every hostname under a domain that ever appeared in a public TLS certificate — with certificate counts, first/last seen and live DNS status.

3 hosts · 213 ms

HostCertsFirst seenLast seenDNS
u410.com 7 2026-04-28 2026-09-16 nodata
*.u410.com 7 2026-04-28 2026-09-16 —
public.u410.com 9 2026-05-25 2026-09-20 ok

Programmatic access, with DNS A records: API GET /v1/hosts/u410.com (API key for paging).

Shown here: hostnames with a certificate that is valid now or expired within the last 90 days. The full history since 2013 — hostnames whose last certificate expired earlier — is a Pro plan method: GET /v1/hosts-history/u410.com.